To the Editor: We are writing to request the
retraction of our article in the March 26, 2003, issue of JAMA1 due to the discovery of a data
error. The article was based on a nested case-control study in which we examined
the relation between antibody titers against Epstein-Barr virus (EBV) and
risk of developing multiple sclerosis (MS). To protect confidentiality, only
the investigators at the Department of Defense Serum Repository (DoDSR) had
access to the link between serum aliquots provided for serological analyses
and case-control status or other covariates. Laboratory results were therefore
sent to the DoDSR, where they were linked with the covariates of interest,
and sent back to the other study investigators as an electronic file stripped
of unique identifiers. Although the personnel linking the data at the DoDSR
are highly trained and experienced in handling the huge database comprising
millions of records, we discovered that in this instance the matching between
laboratory results and remaining data were done incorrectly, apparently because
of incorrect sorting of one of the files.

We have now repeated our analyses on the correctly matched data. With
one exception, there were no errors in the case/control assignment of the
samples. Several dates of blood collection, however, were erroneously assigned,
obscuring important temporal variations in antibody titers among the cases.
Overall, analyses of the correct data still support the strong and highly
significant association between anti–EB nuclear antigen titers and risk
of MS as we originally reported, but it has become apparent that this association
is strongly modified by age. Antibody titers of cases and controls were virtually
identical in samples collected before age 20 years. However, while titers
in controls remained constant, antibody titers of the cases increased, reaching
a maximum between ages 25 and 29 years, followed by a plateau. As discussed
in the article based on the corrected data,2 this
is a new and important finding that may be critical to the understanding of
the relation between EBV and MS.

We apologize for the inconvenience caused to JAMA and its readers by the publication of incorrect data.